Crystal engineering using anilic acids and dipyridyl compounds through a new supramolecular synthon

The anilic acids, 2,5-dihydroxy-1,4-benzoquinone (1a), 2,5-dibromo-3,6-dihydroxy-1,4-benzoquinone (bromanilic acid; 1b), 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid; 1c), and 2,5-dicyano-3,6-dihydroxy-1,4-benzoquinone (cyananilic acid; 1d), were cocrystallized with rigid organic ligands containing two pyridine rings, 2,4-bipyridine (2a), 4,4'-bipyridine (2b), 1,2-bis(2-pyridyl)ethylene (3a), 1,2-bis(4-pyridyl)ethylene (3b), 2,2'-dipyridylacetylene (4a), 3,3'-dipyridylacetylene (4b), and 4,4'-dipyridylacetylene (4c). Fourteen complexes 5-18 were obtained as single crystals, and their crystal structures were successfully determined by X-ray analysis. All complexes except those with 2a are 1:1 and are composed of an infinite linear or zigzag tape structure, the formation of which is ascribed to intermolecular O-H...N, N(+)-H...O, or N(+)-H...O(-) hydrogen bonds or a combination of these between the anilic acids and the dipyridyl compounds. In the complexes 5 and 6, no infinite tape structure is observed although the molecular units connected by a similar hydrogen-bonding pattern are formed. For the 1:1 complexes, we have found two types of stacking arrangements, segregated stacks (7, 9, 12-15, 18) and alternated ones (8, 10, 11, 16, 17). In the complexes of 1c with the series of dipyridylacetylenes 4 (14, 15, 17), the neutral, dication, and monocaction states are formed depending on the nitrogen positions, which can be attributed to the different basicity of the pyridyl groups.     

Halogenation of N-substituted para-quinone monoimines and para-quinone monoximes ethers: IX. Halogenation of N-aroyl-2,6(3,5)-dimethyl-1,4-benzoquinone monoimines and their reduced forms

At the halogenation of N-aroyl-2,6(3,5)-dimethyl-1,4-benzoquinone imines we found the halogenation of methyl groups to occur. The bromination of N-aroyl-2,6-dimethyl-1,4-benzoquinone imines yielded 3,6-dibromo-2,6-dimethyl-5-aroyloxycyclohex-2-ene-1,4-diones due to the strong acceptor property of the ArCO group and high redox potentials of N-aroyl derivatives. In the chlorination of N-aroyl-3,5-dimethyl-1,4-benzoquinone imines the chlorine addition to the C=C bond of the quinoid ring proceeded both by the trans- and syn-scheme.     

Electrochemical reduction of 1,4-dihalobutanes at carbon cathodes in dimethylformamide

Cyclic voltammetry and controlled-potential electrolysis have been employed to investigate the electrochemical behavior of 1,4-dibromo-, 1,4-diiodo-, 1-bromo-4-chloro- and 1-chloro-4-iodobutane at glassy carbon cathodes in dimethylformamide containing tetramethylammonium perchlorate. Depending on the identity of the 1,4-dihalobutane electrolyzed and the choice of potential, reduction of these compounds leads to a myriad of products including cyclobutane, n-butane, n-octane, 1-butene, cis-and trans-2-butene, 1,3-butadiene, ethylene, 1-chlorobutane, 1-bromobutane, 1-iodobutane, 1-iodooctane, 1,4-dichlorobutane, 1,8-dichlorooctane, and 1,8-diiodooctane. Experiments involving the use of proton donors (phenol and 1,1,1,3,3,3-hexafluoro-2-propanol), a radical trap (norbornylene), and several deuterium ion or atom donors have been utilized to elucidate the mechanisms by which the various electrolysis products are formed.     

气相色谱-质谱法研究多卤代产物的组成和结构

在制备取代的１,４－己二烯过程中,在钯（Ⅱ）催化下烯丙基溴对１,４－二氯－２－丁炔的加成反应生成了一系列未曾预料的复杂产物,运用气相色谱－质谱法（ＧＣ－ＭＳ）对产物进行了逐个分析。分析结果显示：（１）８个化合物中除两个为预期产物外,其余均为氯和溴交换反应的副产物,并且８个化合物中的每两个为一对几何异构体;（２）４对几何异构体中Ｚ／Ｅ的比例随着分子量的增加而逐渐下降。     

质体醌类化合物的合成研究

醌环的取代基对醌类化合物进行光合作用的电子传递过程有很大影响. 我们设想若能在保持与醌环上的甲基相近体积的条件下, 将其中一个甲基换成氯原子, 这样, 这类化合物醌环上的电子密度显然会低于质体醌, 从而进一步研究它们在光合作用中的作用, 有助于进一步阐明光合作用机制, 以3-氯-2-甲基苯胺为原料, 经氧化, 自由烷基化反应, 合成了十六个具有不同长侧链结构的质体醌类似物.     

Formation of dimer-type ketals in the reaction of 2,4,6-trichlorophenol and 2,4,6-trichloro-m-cresol with calcium hypochlorite in methanol: conversion to quinones and other compounds

2,4,6-Trichlorophenol (2) and 2,4,6-trichloro-m-cresol (5) react with calcium hypochlorite (Ca(OCl)(2)) in MeOH to give respectively dimer-type ketals 2-(2',4',6'-trichlorophenoxy)-4,4-dimethoxy-6-chlorocyclohexadien-2,5-one (6) and 2-(3'-methyl-2',4',6'-trichlorophenoxy)-4,4-dimethoxy-5-methyl-6-chlorocyclohexadien-2,5-one (7). Ketal 6, which was too unstable to be isolated, and 7 hydrolyzed in H(2)O/HCl to 2-(2',4',6'-trichlorophenoxy)-6-chloro-1,4-benzoquinone (8) and 2-(3'-methyl-2',4',6'-trichlorophenoxy)-5-methyl-6-chloro-1,4-benzoquinone (9), respectively. Ketal 6 and quinone 8 were also produced when 2 and Ca(OCl)(2) reacted in DMF, followed by addition of MeOH and H(2)O, respectively. The mechanisms of these reactions are examined. Conversion of the ketals and quinones to other products is described.     

7-氯-[1，2，3，4]-四氢吩嗪-[2，3]-并富勒烯[60]的合成

60富勒烯及其衍生物因其结构的特殊性,在有机超导、分子磁性、有机发光材料、分子器件、非线性光学活性、能量代谢和生物活性等[1]方面表现出独特的性能和潜在的应用前景,是非常活跃的研究领域之一.     

Reaction of <Emphasis Type="Italic">N</Emphasis>-chloro-1,4-benzoquinone imines with thiols

N-Chloro-1,4-benzoquinone imines reacted with arenethiols to give different products, depending on the conditions and initial quinone imine structure. N-(Arylsulfanyl)-1,4-benzoquinone imines were obtained as a result of nucleophilic substitution of the chlorine atom, and 1,4-benzoquinone imines containing an aryl-sulfanyl substituent in the quinoid ring were formed according to the radical mechanism. The reactions of N-chloro-1,4-benzoquinone imines with heterocyclic thiols afforded only the corresponding chlorine substitution products.     

Microwave-mediated Claisen rearrangement followed by phenol oxidation: a simple route to naturally occurring 1,4-benzoquinones. The first syntheses of verapliquinones A and B and panicein A

The naturally occurring 1,4-benzoquinones 2-methoxy-6-propyl-1,4-benzoquinone (1), 2-methoxy-6-pentyl-1,4-benzoquinone (primin 2), 2-methoxy-6-pentadecyl-1,4-benzoquinone (3), 2-methoxy-6-heptadecyl-1,4-benzoquinone (dihydroirisquinone, pallasone B; 4) were synthesized by a simple protocol involving microwave accelerated Claisen rearrangement of allyl ethers 10, followed by hydrogenation of the side chain alkene, and oxidation to the quinone. The Claisen-based methodology was extended to the first synthesis of the marine benzoquinones verapliquinones A and B (5 and 6), and panicein A (7). Isoarnebifuranone (9) was also synthesized by a similar strategy.     

New NH-substituted 1,4-naphtho- and 1,4-benzo- quinones: Synthesis,characterization and potential antiproliferative effect against MDA-MB-231 cells

Abstract

Eleven new alkyl and aryl amino quinones were synthesized from quinones (2,3-dibromo-1,4-naphthoquinone 1, 2-bromo-1,4-naphthoquinone 2, p-benzoquinone 3 or 2,6-dichloro-1,4-benzoquinone 8) with primary amines. The structures of all compounds were characterized by spectroscopic technics and elemental analysis. The structure of 2-((6,6-Dimethylbicyclo[3.1.1]heptan-2-yl)methylamino)-3-bromonaphthalene-1,4-dione (5a) was established by single crystal diffraction. 2-(2-(Ethylthio)ethylamino)naphthalene-1,4-dione (6b) was found to have noteworthy antiproliferative effect against MDA-MB-231 cells.     

Metal carbonyl derivatives of 1,4-quinone and 1,4-hydroquinone

CpMoMn(CO)5(mu-S2), 1 reacts with 1,4-benzoquinone to yield CpMoMn(CO)5(mu-S2C6H2O2), 2 containing a 1,4-quinonedithiolato ligand formed by replacing two of the hydrogen atoms on one of the C-C double bonds of 1,4-benzoquinone with sulfur atoms from the disulfido ligand in 1. Compound 2 was reduced with hydrogen to yield CpMoMn(CO)5[mu-S2C6H2(OH)2], 3 which contains a 1,4-hydroquinonedithiolato ligand. Compound 3 was reoxidized to 2 with ferrocenium hexafluorophosphate.     

Synthesis of 2-chloro-4,6-di(heteroaryl)pyrimidines

A practical method for the preparation of 2-chloro-4,6-di(heteroaryl)pyrimidines and their 5-methyl homologues from readily available 2-chloropyrimidine and 2-chloro-5-methylpyrimidine, respectively, is described. The method is based on the addition reactions of heteroaryllithium reagents with chloropyrimidines followed by dehydrogenation of the resultant substituted dihydropyrimidines. The use of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone as the dehydrogenation agent gives the best results. Side reactions in the addition step are discussed.     

Triorganostannylation of halo- and dihaloadamantanes and 5-chloro-2-adamantanone in liquid ammonia by the S(RN)1 mechanism. Relative reactivity of nucleophiles and bridgehead halides

The reactions of 1-bromo-, 1-iodo-, 2-bromo-, 1,3-dibromo-, and 1,4-dibromoadamantane with Me(3)Sn(-) ions were studied in liquid ammonia. The photostimulated reaction of 1-haloadamantane (1-XAd, X = Br, I) or 2-BrAd with Me(3)Sn(-) ions gave in a few minutes excellent yields of the substitution products. The 1,3-dibromo- and 1,4-dibromoadamantane with Me(3)Sn(-) ions also reacted very fast under irradiation to give the disubstitution product in good yields. In competition experiments, 1-ClAd is 5.3 times more reactive than 5-chloro-2-adamantanone (9) toward Me(3)Sn(-) ions in liquid ammonia. When the nucleophile is the Ph(2)P(-) ion, 1-ClAd reacts 2.4 times faster than 9. This is the first time that no redox catalysis was observed when the bridgehead compound bears a carbonyl group as a pi acceptor. On the other hand, the nucleophile Me(3)Sn(-) ion was ca. >1000 times more reactive than Ph(3)Sn(-) ions toward 1-adamantyl radicals, in contrast to the behavior of aryl radicals, where both nucleophiles have the same reactivity.     

Synthesis and dienophilic behavior of (S)-2-cyano-3-(p-tolylsulfinyl)-1,4- benzoquinone

Hydrocyanation of 2-(p-tolylsulfinyl)-1,4-benzoquinone (2) followed by oxidation with PhI(OAc)(2) gives 2-cyano-3-(p-tolylsulfinyl)-1,4-benzoquinone (1). The generation of 1 in the presence of cyclic and acyclic dienes affords the Diels-Alder adducts with a complete chemo- (only reaction with the sulfinyl-substituted double bond takes place), regio- (controlled by the cyano group), and endo selectivity (with respect to the quinone moiety), whereas the pi-facial selectivity is dependent on the structure of the diene.     

Iron pentacarbonyl assisted photochemical route to 2,5- and 2,6-divinyl-substituted 1,4-benzoquinones from 1-ene-3-ynes

Photochemical reaction between the enynes, (Z)-1-methoxybut-1-ene-3-yne, 1 or isopropenyl acetylene, 2 with CO in presence of Fe(CO)₅ yields the 2,6- and 2,5-divinyl-substituted 1,4-benzoquinones: 2,6-bis{(Z)-2-methoxyvinyl}-1,4-benzoquinone (3, 42%), 2,5-bis{(Z)-2-methoxyvinyl}-1,4-benzoquinone (4, 31.5%), [{η²,η²:2,6-di(prop-1-en-2-yl)-1,4-benzoquinone}tricarbonyliron] (5, 45%), and {η²,η²:2,5-di(prop-1-en-2-yl)-1,4-benzoquinone}tricarbonyliron] (6, 65%).     

13C-NMR.-Substituenteninkremente der N3-Gruppe in Azido-1,4-benzochinonen

¹³C-NMR. Substituent Increments of the Azido-group in 1,4-Benzoquinones The empirical substituent increments of the azido-group in 1,4-benzoquinones have been derived from the ¹³C-NMR. chemical shifts of 2-azido-5-chloro-1,4-benzoquinone. The validity of the obtained values was tested by comparison of the empirical and computed ¹³C-NMR. chemical shifts of other azido-chloro-1,4-benzoquinones.     

Selective favorskii rearrangement in macrocyclic rings

A mixture of 2,2-dibromo-12-chlorocyclododecanone (IIa) and 2,12-dibromo-2-chlorocyclododecanone (IIb) by Favorskii rearrangement gave selectively methyl 2-chloro-1-cycloundecene-1-carboxylate (IIIa).     

Spectrophotometric and fluorescence quenching studies of the charge transfer complexation of (4-dimethylamino-benzylidene)-(4,6-dimethyl-pyrimidin-2-yl)-amine with some organic acceptors

The interaction of organic acceptors such as tetrafluoro-1,4-benzoquinone (p-TFQ), tetrachloro-1,4-benzoquinone (p-TCQ), tetrachloro-1,2-benzoquinone (o-TCQ), tetrabromo-1,4-benzoquinone (p-TBQ), tetrabromo-1,2-benzoquinone (o-TBQ) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) with (4-dimethylamino-benzylidene)-(4,6-dimethyl-pyrimidin-2-yl)-amine (SB) as donor is studied spectrophotometrically and fluoremetrically in dichloromethane and trichloromethane. The association constant (K), thermodynamic parameters (ΔG°, ΔH° and ΔS°), oscillator strength (f), transition dipole moment (μ) and stoichiometric ratio are calculated using Benezi-Hildbrand's, Job and straight-line methods, respectively. The results reveal that the interaction between the donor and acceptors is due to π-π* transitions by the formation of radical ion pairs. The fluorescence quenching of SB with different organic acceptors is investigated. The results reveal that the fluorescence quenching obeys the static type mechanism via charge transfer complex formation in the ground state. The effect of temperature on the equilibrium constants of the CT complexes is also studied.     

New type of quinone-quinone complexation in the reaction of 2,5-dichloro-1,4-benzoquinone with morpholine at high pressure

The complex of tetralcis(morpholino)-1,4-benzoquinone with 2,5-bis(morpholino)-1,4-benzoquinone of 2 : 1 stoichiometry was obtained in 9 % yield in the reaction of 2,5-dichloro-1,4-benzoquinone with morpholine at high pressure.Translated from Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 488–490, February, 1996     

An investigation of oxidative animation of 2-methyl-1,4-benzoquinone with pyrrolidine

Oxidative amination of 2-methyl-1,4-benzoquinone with pyrrolidine yielded 2-methyl-6-pyrrolidino-1,4-benzoquinone as the major product along with 2-methyl-5-pyrrolidino-1,4-benzoquinone formed as the minor product. No detectable amount of 2-methyl-3,6-bis-(pyrrolidino)-1,4-benzoquinone was observed.